Crush the bourbon biscuits until they look like breadcrumbs. Mix them with melted butter until it’s all nicely combined. Press this mixture into the base and along the sides of a pie dish (I used a 10-inch/25cm dish). Pop it into the fridge to chill while you prepare the filling.
Place the chocolate and salt in a heatproof bowl. In a saucepan, warm up the milk, cream, and sugar until it’s steaming. Whisk the egg yolks to loosen them up, then pour the warm cream mixture over the yolks and whisk it all together. Pour this back into the pan and stir it frequently over medium-low heat until it thickens and coats the back of a spoon.
Take it off the heat and pour this lovely mixture over the chocolate and salt, whisking until the chocolate melts. Pour this over the biscuit base and let it chill for about four hours, or until it’s completely cool and set.
When you’re ready to serve, spoon the softly whipped cream over the top, and if you fancy, grate some chocolate over it. Enjoy your delicious homemade mud pie!